1. Field of the Invention
The present invention relates to a time axis correction device for a signal having a time axis fluctuation such as a signal reproduced from a recording medium.
2. Description of the Prior Art
A signal reproduced from a recording medium such as a signal readout from a video disc or a video tape is generally accompanied by a time axis fluctuation. In the case of a signal carrying color video information, for example, such a fluctuation causes jitter or color shading on the reproduced color image.
In order to reduce the time axis fluctuation, various types of time axis correction devices have been proposed. A variable delay element such as a charge coupled device (CCD), for example, has been used in a video disc player system (VDP). The charge coupled device, however, requires a high frequency pulse drive signal and a plurality of peripheral circuits. Furthermore, a shield member has to be used to prevent the undesirable radiation of high frequency pulse drive signals. In addition, there is a further drawback in that a crosstalk component of time axis correction signals appears at the output video signal.
In the case of a video disc player system, a tangential actuator is provided for controlling the position of pickup spot or point along a tangent of recording track, and a control loop system is used for driving the tangential actuator. Such a type of control system adopts a closed servo loop operation in order to make the sensitivity thereof constant, so that the control system has degraded responsiveness in the high frequency range.
Furthermore, the so called heterodyne system has been adopted in video tape recorder systems. The heterodyne system, however, had drawbacks such that the circuit construction tends to be complicated due to a plurality of peripheral circuits, and such that the separation of chroma signals, which may deteriorate the bandwidth characteristics of a luminance signal and the chroma signal, is necessary.